#include <iostream>
using std::cout;
using std::endl;

namespace wd
{
int num = 10;

void display(){
    cout << "wd::display()" << endl;
}

namespace cpp
{

int num = 100;

void display(){
    cout << "wd::cpp::display()" << endl;
}
}//end of namespace cpp
}//end of namespace wd


void test0(){
    //1.
    cout << wd::num << endl;
    wd::display();
    cout << wd::cpp::num << endl;
    wd::cpp::display();
}

void test1(){
    //2.
    /* using namespace wd; */
    using namespace wd::cpp;
    cout << num << endl;
    display();
}

void test2(){
    //3.
    /* using wd::num; */
    /* using wd::display; */
    using wd::cpp::num;
    using wd::cpp::display;
    cout << num << endl;
    display();

}

int main(void){
    test2();
    return 0;
}
